1USB_CLEAR_HALT(9)                USB Core APIs               USB_CLEAR_HALT(9)
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NAME

6       usb_clear_halt - tells device to clear endpoint halt/stall condition
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SYNOPSIS

9       int usb_clear_halt(struct usb_device * dev, int pipe);
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ARGUMENTS

12       dev
13           device whose endpoint is halted
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15       pipe
16           endpoint “pipe” being cleared
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CONTEXT

19       !in_interrupt ()
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DESCRIPTION

22       This is used to clear halt conditions for bulk and interrupt endpoints,
23       as reported by URB completion status. Endpoints that are halted are
24       sometimes referred to as being “stalled”. Such endpoints are unable to
25       transmit or receive data until the halt status is cleared. Any URBs
26       queued for such an endpoint should normally be unlinked by the driver
27       before clearing the halt condition, as described in sections 5.7.5 and
28       5.8.5 of the USB 2.0 spec.
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30       Note that control and isochronous endpoints don't halt, although
31       control endpoints report “protocol stall” (for unsupported requests)
32       using the same status code used to report a true stall.
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34       This call is synchronous, and may not be used in an interrupt context.
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RETURN

37       Zero on success, or else the status code returned by the underlying
38       usb_control_msg call.
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41Kernel Hackers Manual 3.10         June 2019                 USB_CLEAR_HALT(9)
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